Double-Supported Silica-Metal-Organic Framework Palladium Nanocatalyst for the Aerobic Oxidation of Alcohols under Batch and Continuous Flow Regimes

• Stable and easily synthesized metal-organic framework MIL-88B-NH2 represents an attractive support for catalysts employed in oxidation reactions, which are typically performed under relatively harsh conditions. However, MIL-88B-NH2, the thermodynamic polymorph of the more popular MIL-101-NH2, has been rarely employed in catalytic applications because of a difficult impregnation process caused by the flexible nature of the framework. We report herein a new catalyst denoted Pd@MIL-88B-NH2 (8 wt % Pd), the first example of metallic nanoparticles successfully impregnated in the pores of MIL-88B-NH2. Furthermore, by enclosing the MOF crystals in a tailored protective coating of SiO2 nanoparticles, an even more enduring material was developed and applied to the aerobic oxidation of benzylic alcohols. This doubly supported catalyst Pd@MIL-88B-NH2@nano-SiO2 displayed high activity and excellent performance in terms of endurance and leaching control. Under batch conditions, a very convenient and efficient recycling protocol is illustrated, using a teabag approach. Under continuous flow, the catalyst was capable of withstanding 7 days of continuous operation at 110 degrees C without deactivation. During this time, no leaching of metallic species was observed, and the material maintained its structural integrity.

Ämnesord

Natural Sciences  (hsv)

Chemical Sciences  (hsv)

Naturvetenskap  (hsv)

Kemi  (hsv)

oorganisk kemi  (su)

Inorganic Chemistry  (su)

Organic Chemistry  (su)

organisk kemi  (su)

Nyckelord

palladium nanoparticles

MIL-88B-NH2

aerobic oxidation

teabag catalysis

flow chemistry